Method and apparatus for supplying auxiliary fuel or antiknock fluid to internal-combustion engines



4 Sheets-Sheetl FULL THROTTLE AREA X E. BARTHOLOMEW OARBURETOR VENTLRIVACUUM AT FULL THROTTLE, INCHES MERCURY Nov. 4, 1952 Filed Oct. 7. 19481N VEN TOR.

W E M 0 L 0 H T R A B L R A E LEVEL ROAD LOAD .INTAKE MANIFOLD VACUUM,

mcHEs MERCURY ENGINE SPEED, REVOLUTIONS PER MINUTE GAR SPEED MILES PERHOUR FIGURE 1952 E. BARTHOLOMEW 2,616,404

' 7 METHOD AND APPARATUS FOR SUPPLYING AUXILIARY FUEL 0R ANTIKNOCK FLUIDT0 INTERNAL-COMBUSTION ENGINES File'd Oct. 7, 1948 4 Sheets-Sheet 2INTAKE MANIFOLD VACUUM AT FULL THROTTLE, INCHES MERCURY CARBURETORVENTURI VACUUM AT FULL THROTTLEJNCHES MERCURY I00 95 I AREA X I I FUELANTIKNOOK REQUIREMENT, OOTANE NUMBERS LEVEL ROAD LOAD ass AIRG(')NSUMPTIONi, POUNDS P R HOUR 0 I200 I600 2000 2400 2800 3200 ENGINESPEED, REVOLUTIONS PER MINUTE 3 03 46.8 5 |.O 65.2 7 l.4 8 l.6

GAR SPEED, MILES PER HOUR FIGURE 2 INVENTOR.

EARL BARTHOLOMEW Nov. 4, 1952 E. BARTHOLOMEW 0 METHOD AND APPARATUS FORSUPPLYING AUXILIARY FUEL OR ANTIKNOCK FLUID To INTERNAL-COMBUSTIONENGINES Filed Oct. 7, 1948 Y 4 Sheets-Sheet 3 m umDOE INVENTOR.

EARL BARTHOLOMEW BYg 5 E 2 Nov. 4, 1952 E. BARTHOLOMEW 2,516,404

METHOD AND APPARATUS FOR SUPPLYING AUXILIARY FUEL QR ANTIKNOCK FLUID TOINTERNAL-COMBUSTION ENGINES Filed Oct. 7, 1948 4 Sheets-Sheet 4INVENTOR. EARL BARTHOLOMEW BY 7 Q 2 [III/III Patented Nov. 4, 1952UNITED- STATES PATENT oi p v I 7 $616,404 7 METHon AND AnPARA'rUs:FO'RSUYPPLYYINGJ AUXILIARY FUEL R ANTIKNOCK FLUID 'roINTERNAL-COMBUSTION- ENGINES mamm mtmew, Birmingham; Mieligyassi gnor toEthylGorporationy New'York; N'. Y.', a'cor f emnp BewApplication-October 7, 1948, serial-N6. 53,198.

knockfuel or" an antiknockj flu dto an internal cohibus'tion'eiig'inesothatknocking,i isu pressed over-the entire range of engineo'perationwhile atLtl-ie same" time" the consumption of" auxiliary fuelo'r'antikiiock' fluidis"minimized.

I This is acchniplishedhycontrolling thesupply of. auxiliary fluidjointh/jiri' accordancej with var eties initl intake manifoldvacuumand'the rate or air-consumption,tithe engine;

My" invention contemplates the use" of such control for regulating-orproportioning the" supply o'f'an auxiliary fuel. having. higherantiknock properties" than the", pr'imarvflfuelgsupply or. for regulatinthe supply? of an, antiknock" time to the efi'gir'ie'during it's'operation in'order to meet variation in; aritiknoclii requirements withvariation' injengineflcondi 'n's'i' I control of the supply; ofauxiliary fuel or afnt'ilc'iiock-fluid supply "n accordance with theintake manifold vac'u'uifiandratef of airecj'onslumptio'n' isapplicable" toin'jectingf'a supplementaliquantityof high antikiio'ckmeter antiknock fluid" as needed, in" order to augment theantiknockproperties" of the" primaryz'iuel; It is also applicable to theproportioningoflth'e supply of two" fuels wherein an, auxiliary fuel} ofrelatively mg antikno'ck properties is substituted as nee ed 101. part.or' 'alll of a, primar fuel or. releitivel-y w antn noek properties; I

nvent m can i best understood; by referring tothe dfawings which?mentor. a typical nightcqmpressionengifie with automatic transmission.over the' spe'edfrang'e' from 1206 to 3:200" revolutions per minute,-correspondin'g1 .to" vehicle speedsof approximately 30.6- to 81.6.rn'ile's per hour on a level. road, atfull throttle tor variousconditions" of constant intakemanifold vacuum.

Figure 2 is a plot similar to Figure 1 except that curves of constantair-consumption have teen super mposed and the .curveso'f constantinta'lr manifold have been omitted for the sake of clarity. I

Figure 3 is a, Schematic. drawing partiall in Cross-section,illustrating a device for control iii-supp em ntary injection of an"auxiliary fuel or; antikno'ck fluid. L I

Figure 4 is a schematic drawing partially in Cross-Section illustratinga, device'rtr automatically' substituting a, portion or all. of one.fiuel fo -another in accordance with varying engine '(iOiiditiOl'iS'.

In the normal'o'peration"of passenger can truck and bus engines,knocking occurs. duringonly a small fraction of the .totalf operatingtime, and hence during theconsumption. ofi0n1y.a.-sma1l fraction of the.totalgasoline used; Theifuel'anti.-.- knockrequirement ofsuclLenginesusuaHu n;- creases as the, manifold vacuum .decreaseanntilit reaches, a maximum at .fi'ill throttlej conditions. In addition theoctanev requirementjoil thelengine' decreases as engine speedl'increases, I0 1 Iiill throttle operation and. forjcondition'sofconstantintake manifbld a uum; as Campbe Observed; n Figure 11. If a primary.-fuel? is providedi which has sufficient antiknock quality. for.satistactbry operation under all engine/conditions thelieis an excess ofantikn'o'ckquality during a large proportion of the operation .of theengine.

,T-hi's problem can be liest understood by referring, to Figure 1}. in.which curve A...M,' v.13 represents the octanelnumber; reduirementgatfull throttle over a. range .OfQengi'IIeZspEEds .1 or a particular engne ;.Ci1rvefs CD;GH a dlJxenresentv the fuel octane number; requirement;over the speed range. at cohst'antmanifbld vacuums of 5.5, 9.5, 1115and13'.5 inches-of mercury; Iiispectively, The term-.vacuumas;usedfherein is defined as; the differential. in..pressure betweenatmospheric and that at. the. point .015. measurement; The broken lineKL.shows;.the octane number requirement for level. road operationlo vgra ee or. constant, engine; and ne-spend n constant. vehicle speeds...The; data represented in Figure 1 were obtained, Onacarhav-ing anautomatic transmission which operates in..,-.a lower gear atroad speedsbelow about 30. 1111185 1361 hour with resulting. increase: inenginespeed. Therefore the chart does not extend belowia road speed of 30.6miles per houror an-enginespeed of 1200 revolutions per minute. Forcars; having a conventional change-gear transmission the proportionalscales of engine: and. car speed in high gear would be extendedto theleft, as would curves AMB,.,CD,.E F, GHand- IJ,

It is observedthat this engine -.wou1d.-.ret1uire l per cent.

octane number fuel, the engine would knock at all combinations of speedand manifold pressure above those represented by the 77 octane numberline, which is the solid straight line connecting points G and M. Underall other conditions this engine would give knock-free operation on thisfuel.

In an attempt to solve the problem of excess of fuel antiknock quality,it has previously been proposed by others to supply, in the conventionalfuel tank of the vehicle, a primary fuel having suificient antiknockquality at reduced throttle openings (for example at manifold vacuum inexcess of the range of 6-11 inches of mercury) and to supplement thiswith appreciable amounts of an auxiliary fuel of relatively highantiknock quality by injection from an auxiliary tank when the throttleis in more nearly open or the fully open position. Usually the highantiknock quality fuel is injected into the intake manifold at somepoint between the carburetor and the cylin- 'ders;

Suchprevious injection devices'have been designed to cut off theinjection of the high antikno'ck quality fuel when the vacuum in themaniifold reaches approximately 6 to 11 inches of mercury. As a resultof this method of control,

injection occurs over the entire speed range, when the manifold vacuumis less than that for ,be operated on a relativel low antiknock fuel of77,octane number, it would be necessary to ,set the device to feed thehigher octane fuel during all engine operation at which manifold vacuumis less than 11.5 inches of mercury in order to prevent knocking at lowspeeds. With this system, injection between 1200 and 3200 revolutionsper minute would be made at all operating conditions within both area X(defined by points A, M, G) and shaded area Y (defined by points G, M,B, H).

As the engine speed is increased, the range of manifold vacuum overwhich injection is re- :quired becomes progressively smaller until, atabout 2700 revolutions per minute, injection is needed only at manifoldvacuum below 5.5 inches of mercury. At this latter speed, all the fluidinjected at manifold vacuum between 5.5 and 11.5 inches of mercury wouldbe wasted.

At engine speeds of 2900 revolutions per minute and higher, injection isnot required, hence there would be a, complete waste'of the auxiliaryfuel injected.

Furthermore, with injection controlled only by manifold vacuum, on alevel road at constant speeds above '72 miles an hour, injection wouldbe made continuously although it is not required.

'At low speed, substantial enrichment of the mixture beyond thatordinarily employed causes no significant loss of engine power. Howeverat high engine speeds the loss may be as much as Thus in addition to thewaste of high antiknock fuel at high speed associated with injectiondevices controlled by manifold vacuum alone, there is a substantial lossof engine power. Waste of auxiliary fluid when injection is controlledby manifold Vacuum alone could be avoidest octane requirement of theengine, as for ex- 4 ample octane number. In this case the injectiondevice could be set to stop the flow of auxiliary fluid at a lowermanifold vacuum of about 6.0 inches of mercury thereby eliminatinginjection at car speeds in excess of about 61 miles per hour. However,the use. ofa primary fuel having anoctane'number so close to that of thesecondary fuel defeats the purpose of supplementary fuel injection,Whose function is to permit the use of a primary fuel of relatively lowantiknock value during most of the operation.

A similar waste in fuel antiknock quality results from the use ofmanifold vacuum alone for proportioning two fuels, wherein an auxiliaryfuel of relatively [high antiknock quality is substituted for a primaryfuel of relatively low antiknock quality. In this case high antiknockquality is wasted whereas when an additional fluid is added both fueland high antiknock quality are wasted.

It is, therefore, an object of this invention to provide amethod andmeans forreducing' or stopping the flow of auxiliary fuel or antiknockfluid as the speed of the engine is increased, in order to minimize theuse'andyetmeet the antiknock requirements of the engine.v In other wordsmy object is to eliminateinjection under conditions represented by areaY and toinject only under conditions represented by area X of Figure 1.A further object of my invention is to obtain such knock-freeperformance of the engine with substantially no loss of engine power atthe higher speeds.

I accomplish, these objects in the following manner: In addition to acontrol device actuated by the manifold vacuum, I employ a secondvacuum-actuated element which is coordinated with the one actuated bythe manifold vacuum. The second element is operated by the vacuum in aventuri, which may be, the conventional carburetor venturi, locatedahead of the throttle. The vacuum in the venturi is directly related tothe rate of air-consumption. As the flow of air becomes greater withincrease in engine speed or throttle opening, the vacuum in the venturiincreases, tending first to reduce and then to stop the flow ofauxiliary fuel.

The control of auxiliary fuel solely by change of vacuum in the venturias the rate of air-consumption changes is more wasteful of highantiknock fuel than control by manifold vacuum alone. To illustrate,reference is made to Figure 2 which is similar to Figure 1 except thatcurves of constant vacuum are omitted for sake ofclarity,,and curves ofconstant rates of air consumption are superimposed, indicated by thequantities 385, 520, 636, 728, and 810 which express pounds per hour.

If the injection valve were controlled by Venturi vacuum alone and itwere desired to operate this engine on a primary fuel having 77 octanenumber, the injection valve would be adjusted to close at a Venturivacuum of approximately 4.2 inches of mercury corresponding to an airflow of 810 pounds per hour, i. e. the air consumption at full throttleat 2900 revolutions per minute (point M). At higher speeds, the fullthrottle octane number requirement is less than 77. By this controlalone, injection would occur ona level road under all constant speedengine conditions represented by area X (previously defined) and area Z(defined by G, M, N, L, K), i. e. all the area above the level load lineK-L. Areas below line KL represent conditions of operation wherein thevehicle is either decelerat: ing or descending a grade. With this methodof 5 control-,. flow of auxiliary fluid. would also occur under thelatter conditions; represented by the 'area extending below line K-L.'Waste of antikn'o'c'k material ismore' pronouncedthan when control bymanifold vacuum is used alone.

Thus it is seen that neither control alone is suffibient to provideknock-free performance without waste of antiknock quality,.fu'el orboth. However, whenthe injection valve is under the joint control of themanifold vacuum and the venturi vacuui'n as sh'own in Figures '3 and 4and subsequently described herein, the areas or the two diaphragr'nssubjected to these two vacuums'can be: proportioned so as to providecom- I plete cutoff along the: broken line connecting pointsGrand M in:Figures 1 and 2. Injection, then; occurs-only'under engine conditionsrepresented by the area above this line where the additional'antiknockquality is required. Also the joint control-,. modulation of flow isprovidcd so2that-the amount-of high octane material is approximatelyproportioned to the varying conditions under which knocking. would occuron the primary fuel.

The broken line does not-exactly follow thestraight line connectingpoints G and M and therefore: at some engine conditions the antikn'ock'requirement would not be met by about one: octane number.

were-desired, a, primary fuel of '78 octanenumber could be-used. I

' Referring-to Figure 3, a device-is illustrated for controllingsupplemental injection jointly-by intake manifold' and Venturi vacuum.Fuel line H} is connected to a; conventional, carburetor I.I and-to econventional pump and fuel supply (not shown). Fuel fed to thecarburetor is referred tointhespecification and claims as the primaryfuel or fluid. In general it is a fuel ofrelatively} low antiknockproperties, composed in whole. or in part of hydrocarbons and inmostcases containing an anti'knock agent such as tetraethyl lead; However itmay contain other antiknock agents or other-fuels such as alcohols. Theprimary fuelisfed into venturi l2 throughthe conventional carburetor jet31. The .total' quantity consumed is controlled by the manually operatedthrottle l3- ,-.in:t-he usual manner.

The auxiliary fuel or antiknocl; fluid is containedin supply tank [4.This supply of material is referred to herein as auxiliary fuel orauxiliary antiknockflu'id. It may be a hydrocarbon fuel ofhigherantiknock qualitythan the primaryfuel and may contain an antiknockagent such astetraethyllead or it may be an entirely difierent type offuel-which may contain antiknock agents. It is. also within the scope ofmyinvention that the auxiliary fluid comprise only an antiknock materialsuch as aniline, tetraethyllead or other. antiknocksubstances whichmayor may not; be

fuels withinthe usual meaning ofthe term-. The auxiliary fluidshouldhave sufficiently high antioperation-from iioatbow-l 21, intopassageway 3},

This is insignificant but,; if operation without the slightest trace ofknock 6 throughujet'i'z, to'th'eventuri l2,:-to intake main:- f'o'ldi 24and thence to the cylinders'ofthe engine". Iieakage'f'from chambers 25and 26- is' prevented by bellows type seals "21. Chamber 2 5r'connectsthrough line 28 to the intake manifold 24 ,v and chamber 26 throughpassageway 29-to the venturi' l2: Thus means areprovided for actuating)diaphragms H and I8 'byvacuums inthe intake manifold and the venturi,and for" applying this action to" the valve stem. An increase "inmanifold-"vacuum due either to a decreased throttle opening: or anincrease in Venturiva'cu'umdueto increasein rate of air flow through theventuri 'willl tend-to close valve 35. At all timesthe: total forceacting on the valve stem is the sumofthe' forces produced by the twodiaphragm's'. The injection valve and the control diaphragms can pesodesigned thatthe rate-of reduction of flow ofauxiliary fuel will followany desiredpattern of'speed and manifold'vacuum for agiven' engin'e andthus permit operation on a primary" fuel having any selected octanenumber. By proper proportionin'g of diaphragms IT and I8 and a'djustmentof the tension onspring 29 by nut-130,- the cut-on pattern illustratedin Figures iandi'2 can be obtained". H

The net effectiveareas of the two diaphragms required to close the valveunder. either of the combln'a'tions'of intake manifold and'carburetorVenturi vacuums, corresponding to points'G and M, is easily calculatedby solving tw'o simultaneous equations. One equation can be setup forthe closing force on the valve at point G. This closing. force is equalto the sum of the" intake manifold vacuum and carburetor Venturi vacuumat point G multiplied by the net'eifec'tivearea of each of theirrespective diaphragms l' land IR. A similar equation can beset. upforthe closing force on the valve at pc'in't'ML These-two closing forcesareequal hence the two equations can be solvedfor" the relative areas ofthe two diaph'ra'gms. The actual areas of diaphragms 1'1 and 18', thecalculated ratio; sh'ould be just sufiici'ent for their combined forcest'o compress the? chosen spring 28' and. close valve 34' underconditions corresponding to points G 'and M. Usually it is desirable tohave the; diaphragms small for convenience. At. the other'speedsandthrottle openings. between points G and. M, the

combined efiect of diaphragms Fl and 18 results- .in the closure of:theinjection valve substantially in accordance with. the broken lineG--'M1'of Fig.-

uresi '1 and; 2. v

once the areas of the two diaphragm's are proportionedior a given engineandxfor a primary fuel of a given octane'number,- approximateadjustments for use with a diiferent-octane 'num ber primary fuel withina reasonable ran e-can be? made-by nut 33;, The size of: jet 22 is soselected that when valve 34 is wideopen, the'jet will fl'ow a sufficientamount of auxiliary fuel to prevent knocking at low speed and wide openthrottle. The relative amount'of auxiliary" fuel required will depend onthe octane number requirement of the engine, and theoctane um ber of theprimary as? well as the-octane. number of the auxiliary fuel. Part ofthe effect of the auxiliary fuel in. reducing knock is due to its'an'tikno'ck blending value, and the remainder results from enrichmentof the" fuel-airrmixtur'e which enters the'cylinders. Enrichment aloneis a fairly effective means of knock suppressiona;

When alcohol isused as the auxiliary fuel with present dayengines, theflow rate is generally in the range of 10 to 40% of mammary fuel flow atwide-open throttle conditions. For over-theroad operation the amount ofalcohol used ordinarily is from 1 to 10% of the primary fuelconsumption, depending on the type of operating conditions encountered.

Another embodiment of my invention is illustrated in Figure 4 which issimilar to Figure 3 in many respects. The device in Figure 3 applies toan operation wherein the primary fuel supply is controlled by a throttleand the additional high antiknock fuel is automatically supplied asneeded. Figure 4 illustrates the use of my device in an operationwherein a relatively high antiknock fuel is substituted in whole or inpart for the primary fuel, as needed. In contrast to the arrangementillustrated in Figure 3 the mixture ratio resulting from the use of thedevice in Figure 4 is always within the range normally supplied byconventional carburetors. The proportioning means for the two fuels iscontrolled jointly by intake manifold and Venturi vacuum in the samemanner as the additional supply of auxiliary fluid is controlled inFigure 3. In Figure 4, float chambers 32 and 33 are used for relativelylow and high antiknock fuels, respectively. Valves 35 and 36 areattached to valve stem l9 and seat in opposite directions so that asvalve .3B'is opening away from its seat to allow more high antiknockfuel to enter passageway 3|, valve 35 is closing toward its seat therebyI reducing the flow of low antiknock fuel to the passageway 3|. Thusproportioning means are provided which are jointly controlled by the twosources of vacuum according to variation in engine. speed and manifoldvacuum in order to meet the antiknock requirements of the engine. Theuse of my device for this type of operation minimizes the consumption ofhigh antiknock quality fuel without increasing the total quantity offuel normally used. With this type of opera,- tion, the amount of highoctane fuel used depends on the fuel antiknock requirement of theengine, the octane number of both fuels, and the type of operatingconditions. With present day engines and fuels, the amount of highoctane fuel consumed usually is from to 50 per cent of the totaldepending on the vehicle and type of operation on the road.

During the start of acceleration from low speed with an automatictransmission, or inhigh gear with a conventional change-geartransmission, the engine is usually operated at fullthrottle by theaverage driver of the vehicle. If the driver continues acceleration atfull throttle, as he frequently does, the vacuum in the carburetorventuri increases with the increase in engine speed, causing diaphragmI! to move the auxiliary fuel valve toward the closed position. When aspeed and Venturi pressure corresponding to point M of Figures 1 and 2have been reached; the valve closes completely. At higher speeds noinjection occurs. With a conventional change-gear transmission,acceleration in first or second gears is often done at part throttle, asmay also be done with an automatic transmission. In this event injectionis cut ofi under conditions represented by broken line GM. Thus the useof my invention generally results in a large saving of auxiliary fuelduring acceleration.

All vehicles operate a part of the time under engine conditionsrepresented by area X of Figures 1 and 2 and would therefore receive thebenefit of modulated injection provided by my device. All vehicles alsooperate a part of the time, and some, such as trucks and busses, thegreater part of the time under conditions represented by area Y ofFigure l and area Z of Figure 2, under which conditions no injectionoccurs during the use of my device. Thus under any condition of engineoperation the use of my invention limits the consumption of auxiliaryhigh antiknock fuel to the minimum necessary for suppression of knockingand thereby effects large savings over devices controlled either bymanifold vacuum or carburetor Venturi vacuum alone.

Other modifications of my invention are possiblewithin the scope of thefollowing claims:

I claim as my invention:

1. In a dual fuel supply apparatus for internal combustion engineshaving a fuel induction system including an air-intake with a Venturitherein, and an air-fuel intake manifold, a proportioning devicecomprising a control valve for a primary fuel, a control valve for asecondary fuel, pressure actuating members for said valves, a pressurechamber associated with each of said members, one of which is adapted tobe connected with the Venturi and the other adapted to be connected withthe intake manifold.

' 2; For an internal combustion engine having a fuel induction systemincluding an air-intake, fuel supply means, and an air-fuel intakemanifold, the improvement comprising proportioning means for varying thesupply of a primary fluid containing a hydrocarbon fuel and havingrelatively low antiknock properties and an auxiliary fluid havingrelatively high antiknock properties, said proportioning means havingoperative means connected therewith and connectable to said inductionsystem, and said operative means fully responsive to joint control bythe rate of air supply through said induction system and by the vacuumin said intake manifold.

3. For an internal combustion engine having a fuel induction systemincluding an air-intake having a Venturi therein, dual fuel supplymeans, and an air-fuel intake manifold, the improvement comprisingproportioning means for varying the supply of a primary fuel havingrelatively low antiknock properties and an auxiliary fuel havingrelatively high antiknock properties, means operating said proportioningmeans comprising a first vacuum actuated element and a second vacuumactuated element cooperatively connected with and jointly operating saidproportionating means, said first element having conduit means in opencommunications with said Venturi applying the vacuum therein to saidelement, and said second element having conduit means in opencommunication with said intake manifold applying the vacuum therein tosaid second element.

4. An auxiliary device for supplying antiknook fluid to an internalcombustion engine, comprising in combination a container for saidfluid-with a passage opening therefrom to the fuel intake system of theengine, dual actuated regulating means for controlling the amount offluid entering said passage, said regulating means being responsive toany change in the vacuum in both the carburetor Venturi and the air-fuelintake manifold and tending to close said passage as said vacuumincreases and to open said passage as said vacuum decreases.

5. An auxiliary device for supplying antiknook fluid to an internalcombustion engine, comprising in combination a container for said fluidwith a passage opening therefrom to the fuel intake system of theengine, a dual actuated valve for Y9- controllingstheamount of fluidentering said pas- -sage,said valvebeing operated by and responsive --tothe combined action of two diaphragms, one

ofwhich: is responsive to any change in the vacuum inv theicarburetorventuri and the other of which is responsive to any change in the vacuumin the intake manifold, each' of said diaphragms tending .toclosesaidvalve as the vacuum to which it is responsive increases, and to opensaid valve as said vacuum decreases.

6. An auxiliary device for supplying antiknock fluid to an internalcombustionengine,comprisin in combination a container for said fluidwith a passage opening therefrom to the carburetor, a dual actuatedsingle actingvalve for controlling the amount -offluid entering saidpassage, said valve being operated by and responsive to the combinedaction of two diaphragms, one of which ism-responsive to any change inthe vacuum in the carburetor venturi and the other of whichis responsiveto any change in the vacuum in the air-fuel intake manifold, each ofsaid diaphragms tending to close said valve as the vacuum to which it isresponsive increases, and to open said valve as said vacuum decreases.

'7. A device for proportioning the relative quantitles of two fuels ofdifferent antiknock rating which are fed to an internal combustionengine, comprising in combination a container for a primary fuel and acontainer for an auxiliary fuel of higher antiknock rating, a passagefrom each of said containers to the carburetor, a dual actuated doubleacting valve for controlling the amount of fuel flowing from each ofsaid containers to the carburetor, said valve being operated by twodiaphragms, one of which is responsive to the vacuum in the carburetorventuri and the other of which is responsive to the Vacuum in the intakemanifold, each of said diaphragms tending to open the container for theprimary fuel and to close the container for the auxiliary fuel as thevacuum to which it is responsive increases, and to reverse saidoperations as said vacuum decreases.

8. A method for changing the antiknock rating of a fuel for an internalcombustion engine in accordance with the antiknock requirements of theengine under different operating conditions which comprises supplying tosaid engine a primary fuel of insufficient antikncck rating to providefor all operating conditions, and admixing with said primary fuel anauxiliary fluid of higher antiknock rating when the operating conditionsof the engine so require, the amount of auxiliary fluid admixed asaforesaid being controlled by the additive effect of the vacuumdependent on the amount of air flowing to the carburetor and the vacuumin the air-fuel intake manifold decreasing as said eifect increases, andincreasing as said effect decreases.

9. A method for changin the antiknock rating of a fuel for an internalcombustion engine in accordance with the antiknock requirements of theengine under different operating conditions which comprises supplying tosaid engine a primary fuel of insufficient antiknock rating to providefor all operating conditions, and admixing with said primary fuel anauxiliary fluid of higher antiknock rating when the operatin conditionsof the engine so require, the amount of auxiliary fluid admixed asaforesaid being controlled by the additive effect of the vacuum in thecarburetor venturi and the vacuum in the air-fuel intake manifold, saidamount decreasing '10 as said effect increases and increasing as saideffect decreases.

10. A method for changing the antiknock rating of a fuel for an internalcombustion engine in accordance with the antiknock requirements of "theengine under different operating conchtions which comprises supplying tosaid engine a primary fuel of insufficient antikncck rating to providefor all operating conditions, and admixing with said primary fuel anauxiliary fluid of higher antiknock rating when the operating conditionsof the engine so require, the amount of auxiliary fluid admixed asaforesaid being controlled by the additive effect of the vacuum in thecarburetor venturi and the vacuum in the air-fuel intake manifold, saidamount decreasing progressively as said effect increases until a pointisreached at which substantially no auxiliary fluid is requiredwhereupon the flow of said fluidisstopped, and increasing progressivelyas said effect decreases beyond the foregoing point.

11. A device for supplying auxiliary antiknock fluid to an internalcombustion engine, comprising in combination a container for said fluidwith a passage opening therefrom to the fuel intake system of theengine, regulating means for controlling the amount of fluid enteringsaid passage, said regulating means being responsive to the combinedeffect of the vacuum dependent on the amount of air flowing to theinduction system of the engine and the vacuum in the air-fuel intakepassage, any increase in either of said vacuums having the samedirectional effect on said regulating means, and any decrease thereinhaving the opposite directional effect.

12. A device for supplying auxiliary antiknock fluid to an internalcombustion engine having throttle means for controlling the main fuelsupply, comprising in combination a container for said fluid with apassage opening therefrom to the fuel intake system of the engine,regulating means for controlling the amount of fluid entering saidpassage, said regulating means being responsive to the combined eifectof the vacuum before said throttle dependent on the air flow, and thevacuum after the throttle, any increase in either of said vacuumstending to decrease the flow of fluid entering said passage and anydecrease in either of said vacuums tending to increase said flow offluid.

13. A device for supplying auxiliary antiknock fluid to an internalcombustion engine, comprising in combination a container for said fluidwith a passage opening therefrom to the fuel intake system of theengine, regulating means for controlling the amount of fluid enteringsaid passage, said regulating means being responsive to the combinedeffect of the vacuum in the carburetor venturi and the vacuum in theairfuel intake manifold and tending to increase the flow of fluidthrough said passage as either of said vacuums decreases and to decreasethe flow of fluid through said passage as either of said vacuumsincreases.

14. A device for proportioning the relative quantities of two fuelswhich are fed to an internal combustion engine, comprising incombination a container for a primary fuel and a container for anauxiliary fuel for enhancing the antiknock rating of the primary fuel, apassage from said containers to the carburetor, a proportioning devicefor controlling the amount of fuel flowing from each of said containersto the carburetor, said proportioning device being responsive to thecombined effect of the vacuum before the throttle dependent on the airflow, and the vacuum after the throttle, any increase'in either of saidvacuums tending to decrease the proportion of auxiliary fuel in saidpassage and any decrease in either of said vacuums tending'to increasethe proportion of said auxiliary fuel.

15. A method for changing the antiknock rating of a fuel for an internalcombustion engine in accordance with the antiknock requirements of theengine under difierent operating conditions which comprises supplying tosaid engine a primary fuel of insuflicient antiknock rating to providefor all operating conditions, and admixing with said primary fuel anauxiliary antiknock fluid when the operating conditions of the engine sorequire, the amount of auxiliary fluid admixed as aforesaid beingcontrolled by combining the efiects of the vacuum dependent on theamount'of air flowin to the carburetor and the vacuum in the air-fuelintake manifold, said effects being combined in such manner that aseither of said vacuums decreases it tends to increase the amount ofauxiliary fluid admixed with the primary fuel and as either of saidvacuums increases it tends to decrease the amount of auxiliary fluidadmixed with the primary fuel.

EARL BARTHOLOMEW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

